CODEWITHSUNDEEP
sqloracle-database
Nil Pun
Nil Pun

Reputation: 17383

How to update with inner join in Oracle

Could someone please verify whether inner join is valid with UPDATE statment in PL SQL? e.g.

Update table t
set t.value='value'
from tableb b inner join
on t.id=b.id
inner join tablec c on
c.id=b.id
inner join tabled d on
d.id=c.id
where d.key=1

Upvotes: 8

Views: 50126

Answers (2)

Vincent Malgrat
Vincent Malgrat

Reputation: 67782

This synthax won't work in Oracle SQL.

In Oracle you can update a join if the tables are "key-preserved", ie:

UPDATE (SELECT a.val_a, b.val_b
          FROM table a
          JOIN table b ON a.b_pk = b.b_pk)
   SET val_a = val_b

Assuming that b_pk is the primary key of b, here the join is updateable because for each row of A there is at most one row from B, therefore the update is deterministic.

In your case since the updated value doesn't depend upon another table you could use a simple update with an EXIST condition, something like this:

UPDATE mytable t
   SET t.VALUE = 'value'
 WHERE EXISTS 
       (SELECT NULL
          FROM tableb b
         INNER JOIN tablec c ON c.id = b.id
         INNER JOIN tabled d ON d.id = c.id
         WHERE t.id = b.id
           AND d.key = 1)

Upvotes: 15

L Petre
L Petre

Reputation: 1097

update t T  
set T.value = 'value'
where T.id in (select id from t T2, b B, c C, d D
               where T2.id=B.id and B.id=C.id and C.id=D.id and D.key=1)

-- t is the table name, T is the variable used to reffer to this table

Upvotes: 1

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